Frame for fixing optical sheet and backlight module using the same

ABSTRACT

A frame ( 34 ) for fixing an optical sheet ( 31 ) thereon includes a frame body ( 35 ) and at least a fastener ( 36 ). The frame body includes a plurality of contiguous sidewalls ( 352, 353, 354,  and  355 ) and at least one latching portion ( 358 ) defined on the at least one of sidewalls. The fastener is mounted into the latching portion correspondingly such that the optical sheet is fixed on the top portions of sidewalls of the frame body. A backlight module using the frame is also provided, which has a lightweight, and also can be assembled easily.

FIELD OF THE INVENTION

The present invention relates to a frame typically used in a backlightmodule, more particularly a bottom-lighting type backlight moduletypically used in a liquid crystal display (LCD).

DISCUSSION OF THE RELATED ART

In a liquid crystal display device, liquid crystal is manipulated toprovide images for display. However, liquid crystal is a substance thatdoes not itself illuminate light. Instead, the liquid crystal relies onlight received from a light source, and thereby can display images anddata. In the case of a typical liquid crystal display, a backlightmodule powered by electricity supplies the needed light.

Typically, a bottom-lighting type backlight module includes a pluralityof light sources, a number of optical sheets, and a frame fixing theplurality of light sources and accommodating the optical sheets. Theoptical sheets can be selected from the group consisting of a diffusingplate, a prism sheet, or a brightness enhancement film. The opticalsheets are used to improve the backlight module's optical uniformity.

FIG. 8 shows a typical backlight module 10. The frame 10 includes abottom frame 11, a top frame 12, a plurality of light sources 13, areflective sheet 14, and an optical sheet 16. The bottom frame 111includes a base (not shown) and four sidewalls 112 extending from aperiphery of the base to define a recess 116. A plurality of screw holes114 is defined in top portions of the sidewalls 112. The top frame 12has a frame body 121 defining a rectangular opening 123 therein, and aplurality of screw holes 124 disposed on the frame body 121corresponding to the screw holes 1114 of the sidewalls 112. Thereflective sheet 14 is positioned on the base of the bottom frame 11.The light sources 13 are aligned regularly above the reflective sheet 14in the bottom frame 11. The optical sheet 16 is supported on the top ofthe sidewalls 112 of the bottom frame 11. The top frame 12 can bemounted onto the top of the bottom frame 111 by locking a plurality ofscrews (not shown) through the corresponding screw holes 114 and 124, soas to fix the optical sheet 16 tightly on the top portions of thesidewalls 112.

However, the procedure of assembling the backlight module 10 is complexand complicated, because it requires the screws to be individuallylocked through the screw holes 114 of the bottom frame 111 and the topframe 12. In addition, the top frame 12 makes the backlight module 10relatively heavy, and adds to manufacturing costs.

What is needed, therefore, is a frame and backlight module using theframe which can overcome the above-described shortcomings.

SUMMARY

In one aspect, a frame for fixing an optical sheet thereon according toa preferred embodiment includes a frame body and at least one fastener.The frame body includes a plurality of contiguous sidewalls and at leastone latching portion defined on the at least one of sidewalls. The atleast one fastener is mounted into the latching portion correspondinglysuch that the optical sheet is fixed on the top portions of thesidewalls.

In another aspect, a backlight module according to a preferredembodiment includes a plurality of light sources, at least one opticalsheet and a frame. The same frame as described in the previous paragraphis employed in this embodiment. The optical sheet is fixed on the topportions of the frame body by the fastener mounted into the latchingportion of the frame body. The light sources are regularly arranged inthe frame body under the optical sheet.

Other advantages and novel features will become more apparent from thefollowing detailed description of preferred embodiments when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The components in the drawings are not necessarily drawn to scale, theemphasis instead being placed upon clearly illustrating the principlesof the present frame and related backlight module. Moreover, in thedrawings, like reference numerals designate corresponding partsthroughout the several views.

FIG. 1 is an abbreviated, schematic, exploded isometric view of abacklight module according to a first preferred embodiment of thepresent invention.

FIG. 2 is an enlarged view of a circled portion II of FIG. 1.

FIG. 3 is an enlarged view of a circled portion III of FIG. 1.

FIG. 4 is an enlarged, assembled view of the backlight module of FIG. 1.

FIG. 5 is an abbreviated, schematic, exploded isometric view of a frameaccording to a second preferred embodiment of the present invention.

FIG. 6 is an abbreviated, schematic, exploded isometric view of a frameaccording to a third preferred embodiment of the present invention.

FIG. 7 is an abbreviated, schematic, exploded isometric view of a frameaccording to a fourth preferred embodiment of the present invention.

FIG. 8 is an abbreviated, schematic, exploded isometric view of aconventional backlight module.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made to the drawings to describe preferredembodiments of the present frame and backlight module, in detail.

Referring to FIGS. 1 and 2, a backlight module 30 in accordance with afirst preferred embodiment is shown. The backlight module 30 includes anoptical sheet 31, a plurality of light sources 32, a reflective sheet33, and a frame 34. The frame 34 includes a frame body 35 and twofasteners 36. The frame body 35 includes a rectangular base 351 and foursidewalls 352, 353, 354, and 355 formed at a periphery of the base 351,thereby cooperatively defining a recess 356. The sidewall 353 definestwo latching portions 358 at a top area thereof. The reflective sheet 33is disposed on the base 351. The optical sheet 31 is fixed on top of theframe body 35 by mounting the two fasteners 36 into the two latchingportions 358 of the frame body 35. The light sources 32 are regularlyarranged within the frame body 35 between the optical sheet 31 and thereflective sheet 33. The light sources 32 are configured for emittinglight to the optical sheet 31. The reflective sheet 33 is configured forreflecting light to the optical sheet 31, so as to increase a lightenergy utilization rate of the backlight module 30. The light isrefracted and diffused in the optical sheet 31, so that substantiallyplanar light is outputted from the optical sheet 31. In this embodiment,the optical sheet 31 is a light diffusion sheet.

A supporting ledge 359 is defined along an inner side of top areas ofthe four sidewalls 352, 353, 354, and 355. That is, the supporting ledge359 is configured to be a continuous recessed shelf at top surfaceportions of the four sidewalls 352, 353, 354, and 355. A size of theoptical sheet 31 is configured to conform with a size defined by innerboundaries of the sidewalls 352, 353, 354, and 355 that surround thesupporting ledge 359. Thus the optical sheet 31 can be fittinglyreceived between the sidewalls 352, 353, 354, and 355 and supported onthe supporting ledge 359 of the frame body 35.

The two latching portions 358 are separate from each other but alignedwith each other at the top area of the sidewall 353. Each latchingportion 358 includes two latching slots 3582 and two protrusions 3584.The two latching slots 3582 are separate from each other, and aredefined in an inner surface portion of the top area of the sidewall 353that bounds the supporting ledge 359. The two protrusions 3584 protrudeout from an outer surface of the top area of the sidewall 353 betweenthe two latching slots 3582.

Each fastener 36 includes a mounting plate 361, and a retaining plate362 that extends perpendicularly from a side of the mounting plate 361.The mounting plate 361 defines two openings 3612 therein correspondingto the two protrusions 3584. The retaining plate 362 defines two hookedtabs 3622 at two ends thereof corresponding to the two latching slots3582. Each hooked tab 3622 runs parallel to the mounting plate 361. Asize of the hooked tab 3622 is configured for mating in thecorresponding latching slot 3582, and a size of the opening 3612 isconfigured for receiving the corresponding protrusion 3584. A width ofthe retaining plate 362 is configured to be approximately equal to orlarger than a transverse width of the sidewall 353. When each of thefasteners 36 is mounted onto the corresponding latching portion 358, thetwo protrusions 3584 are inserted into the two openings 3612 forrestricting the mounting plate 361 of the fasteners 36 to slide along anouter surface of the sidewall 353, and the two hooked tabs 3622 are heldin the two latching slots 3582 to keep an inner surface of the mountingplate 361 tightly held on the outer surface of the sidewall 353.Accordingly, the retaining plate 362 can press the optical sheet 31tightly.

Also referring to FIG. 3, the sidewall 355 defines a plurality ofprotruding rims 357 at an inner surface of a top area thereof thatbounds the supporting ledge 359. The protruding rims 357 and thesupporting ledge 359 cooperatively defines a receiving channel 360 forreceiving the optical sheet 31. In addition, a rubber film may be formedon a bottom surface of each protruding rim 357 that faces the supportingledge 359. The rubber film improves friction between the protruding rim357 and the optical sheet 31 in Thereby, the optical sheet 31 isrestricted from moving along a direction parallel to the sidewall 355 inthe event that the frame 34 sustains shock or vibration.

Referring to FIG. 4, the process of assembling the optical sheet 31 ontothe frame body 35 is simple. Firstly, one end of the optical sheet 31 isinserted into the receiving channel 360 of the sidewall 355, so that theoptical sheet 31 is supported on the supporting ledge 359 thereat;secondly, the two fasteners 36 are mounted onto the corresponding twolatching portions 358 of the frame body 35, whereby the protrusions 3584are inserted into the openings 3612, and the hooked tabs 3622 are heldin the latching slots 3582. Therefore, the optical sheet 31 is securedon the securing ledge 359 of the frame body 35 tightly with thecooperative help of the fasteners 36 and the protruding rims 357. Inaddition, compared with the above-described conventional backlightmodule 10, the present backlight module 30 has a relatively lightweightdesign because a top frame such as the top frame 12 is not employed.

The light sources 32 may be selected from the group consisting of coldcathode fluorescent lamps and light emitting diodes. It is to beunderstood that the present backlight module is not limited to onlyemploying one optical sheet 31 such as the light diffusion sheet usedfor uniformly diffusing light emitted from the light source. Rather, anydesired combination of optical sheets may be employed. For example, theoptical sheets can include at least one light diffusion sheet and atleast one prism sheet, or can be other suitable optical sheets forimproving optical performance.

It is noted that the numbers and shapes of the latching portions 358 andthe fasteners 36 are not limited to those as described above andillustrated in relation to the first preferred embodiment. At least onelatching portion 358 and at least one fastener 36 should be consideredto be within the scope of the present backlight module, as long as theapplicable latching portion(s) 358 and fastener(s) 36 cooperatively fixthe optical sheet 31 on the frame body 35. Similarly, the numbers andshapes of the latching slots 3582 and the protrusions 3584 of thelatching portions 358, the numbers and shapes of the openings 3612 andthe hooked tabs 3622 of the fasteners 36, are all not limited to thoseas described above and illustrated in relation to the first preferredembodiment. It is to be understood that the base 351 of the frame body35, and the reflective sheet 33 of the backlight module 30, can beomitted in other embodiments.

Referring to FIG. 5, a frame 40 in accordance with the second preferredembodiment is shown. The frame 40 is similar in principle to the frame34 of the first embodiment, except that fasteners 46 and latchingportions 458 of the frame 40 are different. Each latching portion 458includes two first latching slots 4582 and two latching slots 4584. Thetwo first latching slots 4582 are separate from each other, and aredefined in an inner surface portion of a top area of a sidewall 453 thatbounds a supporting ledge 459. The two latching slots 4584 are definedin an outer surface portion of the top area of the sidewall 453 betweenthe two first latching slots 4582. Each fastener 46 includes a mountingplate 461 and a retaining plate 462. The mounting plate 461 includes twoprotrusions 4612 each protruding out from an inner surface thereof, theprotrusions 4612 corresponding to the two latching slots 4584. Theretaining plate 462 includes two hooked tabs 4622 at two ends thereof,corresponding to the two first latching slots 4582. Each hooked tab 4622is bent down from the retaining plate 462, and is parallel to themounting plate 461.

When each fastener 46 is mounted into the corresponding latching portion458, the two protrusions 4612 are inserted into the two latching slots4584, and the two hooked tabs 4622 are held in the two first latchingslots 4582.

Referring to FIG. 6, a frame 50 in accordance with a third preferredembodiment is shown. The frame 50 is similar in principle to the frame34 of the first embodiment, except that the frame 50 includes fourlatching portions 558 and four fasteners 56. The four latching portions558 are defined on two opposite sidewalls 553 and 555 respectively. Eachlatching portion 558 includes two latching slots 5582 and twoprotrusions 5584. The four fasteners 56 can be mounted onto the fourcorresponding latching portions 558, so as to fix an optical sheet (notshown) on the frame 50.

Referring to FIG. 7, a frame 60 in accordance with a fourth preferredembodiment is shown. The frame 60 is similar in principle to the frame40 of the second embodiment, except that the frame 60 includes aprotruding wall 654 protruding out from inner sides of top areas ofsidewalls 655 of a frame body 65. The protruding wall 654 serves as asupporting ledge 659 for supporting an optical sheet (not shown). Inthis embodiment, the frame 60 is lightweight because the sidewalls 655of the frame body 65 are configured to be thin.

Finally, while particular embodiments have been described above, thedescription is illustrative of principles of the invention and is not tobe construed as limiting the invention. Therefore, various modificationscan be made to the embodiments by those skilled in the art withoutdeparting from the true spirit and scope of the invention as defined bythe appended claims.

1. A frame for fixing an optical sheet thereon, the frame comprising: aframe body comprising a plurality of contiguous sidewalls, and at leastone latching portion defined on at least one of the sidewalls; and atleast one fastener configured to be mounted onto the at least onelatching portion such that the optical sheet is fixed on top portions ofsidewalls of the frame body.
 2. The frame according to claim 1, whereina supporting ledge is defined at inner sides of the top portions of thesidewalls, and the supporting ledge is configured for supporting theoptical sheet thereon.
 3. The frame according to claim 2, wherein thesupporting ledge is defined by a protruding wall protruding out frominner sides of the top portions of the sidewalls of the frame body. 4.The frame according to claim 2, wherein each latching portion comprisesat least one first latching slot defined at an inner surface of the topportion of at least one of the sidewalls adjacent the supporting ledge,and at least one first protrusion protruding out from an outer surfaceof the top portion of the at least one of the sidewalls.
 5. The frameaccording to claim 4, wherein the at least one fastener comprises amounting plate and a retaining plate that extends perpendicularly from aside of the mounting plate, the mounting plate defines at least oneopening therein corresponding to the at least one first protrusion, theretaining plate defines at least one hooked tab corresponding to the atleast one first latching slot, the at least one first protrusion beingconfigured to be inserted into the at least one opening, and the atleast one hooked tab being configured to be held in the at least onefirst latching slot.
 6. The frame according to claim 2, wherein the atleast one latching portion comprises at least one first latching slotdefined in an inner surface of the top portion of at least one of thesidewalls adjacent the supporting ledge, and at least one secondlatching slot is defined in an outer surface of the top portion of theat least one of the sidewalls.
 7. The frame according to claim 6,wherein the at least one fastener comprises a mounting plate and aretaining plate perpendicularly adjoining each other, the mounting platedefines at least one second protrusion protruding out from an innersurface thereof corresponding to the at least one second latching slot,the retaining plate defines at least one hooked tab corresponding to theat least one first latching slot, the at least one second protrusionconfigured to be inserted into the at least one second latching slot,and the at least one hooked tab configured to be held in the at leastone first latching slot.
 8. The frame according to claim 2, wherein theat least one latching portion defines provided on one of the sidewalls,an opposite one of the sidewalls defines one or more protruding rims atan inner surface of the top portion thereof adjacent to the supportingledge, and the protruding rims and the supporting ledge cooperativelydefine a receiving channel configured for receiving a part of theoptical sheet.
 9. The frame according to claim 1, wherein the at leastone latching portion is a plurality of latching portions defined on twoopposite of the sidewalls, the at least one fastener is a plurality offasteners corresponding to the latching portions, and the fasteners areconfigured to be mounted onto the corresponding latching portions tothereby fix the optical sheet on the top portions of sidewalls of theframe body.
 10. A backlight module comprising: a plurality of lightsources; at least one optical sheet; a frame comprising a frame bodyhaving a plurality of sidewalls connected with each other, at least onelatching portion defined on at least one of the sidewalls; and at leastone fastener; wherein the at least one fastener is mounted onto the atleast one latching portion and fixes the at least one optical sheet attop portions of sidewalls of the frame body, and the light sources arearranged in the frame body under the at least one optical sheet forilluminating the at least one optical sheet.
 11. The backlight moduleaccording to claim 10, wherein a supporting ledge is defined at innersides of the top portions of the sidewalls, and the supporting ledge isconfigured for supporting the at least one optical sheet.
 12. Thebacklight module according to claim 11, wherein the supporting ledge isdefined by a protruding wall protruding out from inner sides of the topportions of the sidewalls of the frame body.
 13. The backlight moduleaccording to claim 11, wherein each latching portion comprises at leastone first latching slot defined at an inner surface of the top portionof at least one of the sidewalls adjacent the supporting ledge, and atleast one first protrusion protruding out from an outer surface of thetop portion of the at least one of the sidewalls.
 14. The backlightmodule according to claim 13, wherein the at least one fastenercomprises a mounting plate and a retaining plate that extendsperpendicularly from a side of the mounting plate, the mounting platedefines at least one opening therein corresponding to the at least onefirst protrusion, the retaining plate defines at least one hooked tabcorresponding to the at least one first latching slot, the at least onefirst protrusion being configured to be inserted into the at least oneopening, and the at least one hooked tab being configured to be held inthe at least one first latching slot.
 15. The backlight module accordingto claim 11, wherein the at least one latching portion comprises atleast one first latching slot defined in an inner surface of the topportion of at least one of the sidewalls adjacent the supporting ledge,and at least one second latching slot is defined in an outer surface ofthe top portion of the at least one of the sidewalls.
 16. The backlightmodule according to claim 15, wherein the at least one fastenercomprises a mounting plate and a retaining plate perpendicularlyadjoining each other, the mounting plate defines at least one secondprotrusion protruding out from an inner surface thereof corresponding tothe at least one second latching slot, the retaining plate defines atleast one hooked tab corresponding to the at least one first latchingslot, the at least one second protrusion configured to be inserted intothe at least one second latching slot, and the at least one hooked tabconfigured to be held in the at least one first latching slot.
 17. Thebacklight module according to claim 11, wherein the at least onelatching portion defines provided on one of the sidewalls, an oppositeone of the sidewalls defines one or more protruding rims at an innersurface of the top portion thereof adjacent to the supporting ledge, andthe protruding rims and the supporting ledge cooperatively define areceiving channel configured for receiving a part of the optical sheet.18. The backlight module according to claim 10, wherein the at least onelatching portion is a plurality of latching portions defined on twoopposite of the sidewalls, the at least one fastener is a plurality offasteners corresponding to the latching portions, and the fasteners areconfigured to be mounted onto the corresponding latching portions tothereby fix the optical sheet on the top portions of sidewalls of theframe body.